1. Field of the Invention
The invention relates generally to peristaltic pumps and tubing sets for use therewith. More particularly, the invention relates to a tubing cassette which holds a tube adjacent the peristaltic rollers.
2. Description of the Prior Art
Peristaltic pumps are frequently used in medical and surgical applications in order to pump various fluids during surgical procedures. Numerous designs are known by which the tubing used with peristaltic pumps may be relatively easily engaged with the peristaltic pump roller assembly. These designs generally utilize a cassette in the form of a molded housing which retains a portion of the tubing so that the engagement of the tubing with the peristaltic pump simply requires the attachment of the cassette adjacent the peristaltic pump roller assembly rather than the laborious process of threading a tube around the roller assembly and securing it in place.
One type of tubing cassette is shown in U.S. Pat. No. 5,460,490 (Carr et al.) assigned to the assignee hereof and showing a cassette in the form of a molded block having various channels for holding a tube in a predetermined orientation in the plane of rotation of the peristaltic pump roller assembly. The cassette shown in this patent is retained adjacent the roller assembly by a cam device which presses the cassette against the front panel of the peristaltic pump and holds the tube firmly against the roller assembly without a backing plate. The device is relatively complex and requires more manipulation of the cassette than is desired in certain surgical applications.
Another type of "cassette" is shown in U.S. Pat. No. 5,133,650 (Sunderland et al.) in which the tubing is provided with various fixed molded components which are attachable to complementarily shaped recesses in the pump housing and a pivotable swing arm. The latter may then be swung into place in order to stretch the tube about the peristaltic pump roller assembly. This device is really a two-piece device as opposed to a one-piece cassette and is, therefore, not strictly a cassette as that term is normally understood. However, such "cassettes" are representative of available prior art. A similar "cassette" device is used without a swing arm in the Linvatec C7050 Irrigation Console available from Linvatec Corporation, 11311 Concept Boulevard, Largo, Fla. 33773. This device utilizes a peristaltic pump having a pump roller assembly situated adjacent fixed tube-holding stations designed to be used with a tubing set having fixed molded components secured thereto. The tubing set is used by first placing one of the molded components into one of the tube-holding stations adjacent the roller assembly, then stretching the tube around the roller assembly and securing the other molded component in the other tube-holding station. This arrangement holds the tube in generally a U-shape around the peristaltic pump roller assembly as is often done in peristaltic pumps.
Other cassette arrangements are also known in which a one-piece cassette is used with a pair of latching mechanisms in order to hold the tubing cassette in proper position adjacent the peristaltic pump roller assembly. For example, U.S. Pat. No. 5,433,588 (Monk et al) shows a cassette maintained adjacent a peristaltic pump roller assembly by the cooperative action of a pair of spaced locking surfaces, spaced on either side of the rollers. This device operates with a backing plate so that the peristaltic rollers squeeze the tube between the rollers and the backing plate. The device is relatively complex.
Another known disposable cassette for use with a peristaltic pump is shown in U.S. Pat. No. 4,537,561 (Xanthopoulos). The cassette of this device operates without a backing plate and is secured adjacent the pump by a pair of articulating latch arms which hold opposing sides of the cassette adjacent the pump roller assembly station. While this patent makes a reference to a mechanical or electromechanical arrangement utilized to release this locking mechanism, no such arrangement is shown. However, one can reasonably expect it to be relatively complex since the articulating arms must both be moved simultaneously.
It is accordingly an object of this invention to produce a simple, disposable tubing cassette for use with a peristaltic pump roller assembly.
It is another object of this invention to produce a peristaltic pump roller tubing system which enables a tube to be engaged with a peristaltic pump roller assembly in a single manual operation.
It is a further object of this invention to enable such a tubing cassette to be disengaged from the peristaltic pump roller assembly in a simple manual operation.